Mailbag: Web advertising terminology

Q. I had a couple of questions to throw out for the workshop. I’m just scraping the surface of online advertising and I was wondering if you could go over some of the basics? (Or direct me to where that information is if you’ve already done that.)

Like when you mentioned, “leaderboard, skyscraper, square”, is that strictly pertaining to dimensions or also to ad placement? I’ve got a pretty good handle, (I think) on the design aspects of advertising, but I’m a little lost when it comes to the lingo and I’m afraid I’m going to end up blowing half my budget on a tiny ad in the footer when I thought I was buying header space! (Or something like that.)